India’s Western Ghats, home to countless frog species

In the last decade, at least 200 frog species were found in the Western Ghats – and 41 new species of frogs were discovered in the mountain range last year alone.

A file photo of professor Sathyabhama Das Biju from the University of Delhi, a lead scientist of a project that has discovered 14 new species of so-called dancing frogs in southern India’s lush mountaShow more

NEW DELHI // Priti Gururaj is often in front of a computer, like so many other office workers in Bengaluru. But other times, she’s off in the woods of the Western Ghats — a 1,600 kilometre mountain range running parallel to the south-western coast of India and spanning five states.

A researcher at the Bengaluru-based Ashoka Trust for Research in Ecology and Environment (ATREE), Ms Gururaj sets out late in the evening, trekking through the thick growth, listening for unfamiliar sounds.

All around are wild elephants, snakes and leeches. But what she is really listening for is the call of frogs — more precisely, an as yet unknown call that might belong to an undiscovered species.

In her three years as a doctorate student at ATREE, she has already been involved in the discovery of the Nyctibatrachus kumbara, a night frog the colour of tree bark, living in the Ghats. The discovery will be officially announced in a paper published later this year in a scientific journal.

Over the past decade, out of more than 350 frog species discovered across India, at least 200 were found in the Ghats, according to Ms Gururaj.

Just last year, 41 new species of frogs were discovered in the mountain range.

The Ghats can easily sustain such a heated pace of discovery. Designated by the United Nations Educational, Scientific and Cultural Organization (Unesco) as one of the world’s eight “hottest hotspots” of biological diversity, the mountain range is home to nearly 10,000 species of flowering plants and more than a thousand species of animals.

Despite this, few frog zoologists have explored them, said SP Vijayakumar, a fellow at the National Centre for Biological Sciences in Bengaluru.

“In the late 1800s, the British published a volume called ‘The Fauna of British India’ but after that, for almost a hundred years, there was no research done on amphibians in the country,” Mr Vijayakumar said. “That changed over the last decade.”

There are now more scientists tramping through the Ghats searching for frogs than at any other time in the past, and new technology has also aided the process of discovery.

In addition to the traditional field of morphology, which studies the form and structure of a species, scientists now use molecular genetics to analyse the DNA of an organism. At this genetic level, even minuscule differences between species can be identified.

“Sometimes frogs on adjacent mountain peaks would have diverged from each other,” said Kartik Shanker, at the Indian Institute of Science in Bengaluru. “Once, as I climbed a hill, I heard a frog with a particular call. On the other side of the hill, was a similar frog but with a different call, a different species.”

The particular terrain present in the Ghats helps foster the diversity, Mr Shanker said.

Large valleys separate the mountains, meaning that frogs on adjacent peaks or in valleys have virtually no opportunity to interbreed. As a result, the frogs have diverged into different species, evolving to suit their own specific habitat.

Mr Vijayakumar compares the Ghats to the richly diverse Galapagos Islands in Ecuador, where species have diverged on adjacent islands because the water in between serves as a barrier to dispersal.

Ms Gururaj predicted more discoveries of new frog species living in the Ghats.

“We haven’t even explored many parts of the Ghats fully,” she said. “The eastern slopes, for example — there are very few people who are working there. We’ve all been concentrating on the central and southern part of the Western Ghats, because it has been easier to get forest department permits to work there.”

However, time is not on their side.

In 2011, a government-appointed panel headed by the veteran ecologist Madhav Gadgil released a report declaring all of the Western Ghats an “ecologically sensitive area”. The report recommended restricting damming, mining and industrial activities in many areas adjoining the mountains, to protect the region’s biodiversity.

The mountain range is home to 325 globally threatened species of plants and animals, according to Unesco. More than 40 of these are amphibians.

But India’s environment ministry decided not to act upon Mr Gadgil’s report, relying instead upon the recommendations of another government-appointed panel, led by the scientist and former parliamentarian K Kasturirangan, which proposed fewer restrictions and that suggested designating only a third of the Ghats as “ecologically sensitive”.

Commercial projects that were already ongoing, such as mining on the northwestern fringes of the Ghats, have been permitted to continue. Only in the areas designated ecologically sensitive will projects need to secure approvals from local villagers before beginning work.

But perhaps the discovery of more new organisms by scientists like Ms Gururaj will focus more attention on the need to preserve the Ghats.

“It’s thrilling to find a new species,” she said. “It’s nothing like the pharma company I worked in earlier — the same old data, the same old work. Every time I go into the field, I learn something new.”